Systems and methods for residue collection with improved letter handling capability

ABSTRACT

Systems and methods for the detection of substances (particularly particulate substances) within mail pieces, specifically letters and other “flats” of mail. In particular, the systems and methods are for the detection of residues of Chemical or Biological Warfare Agents (CBWAs) which may be present within the mail pieces. The system is principally designed to be included as part of Dual Pass Rough Cull System (DPRCS) for the collection and detection of the residue when the contaminated mail piece first enters a mail facility and before it is intermingled with other mail pieces. The system also utilizes aerosol chambers using at least two arrays of pinch rollers to provide for decreased incremental changes on mail pieces and decrease the likelihood of mail piece damage.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.11/620,926, filed Jan. 8, 2007 and currently pending, which is aContinuation of U.S. patent application Ser. No. 11/282,268, filed Nov.18, 2005, now U.S. Pat. No. 7,178,379, which is in turn a Continuationof U.S. patent application Ser. No. 10/941,273 filed Sep. 15, 2004, nowU.S. Pat. No. 7,100,422, which is in turn a Continuation-in-Part of U.S.patent application Ser. No. 10/449,612 filed May 30, 2003, now U.S. Pat.No. 6,941,794, which in turn claims benefit of U.S. ProvisionalApplication Ser. No. 60/385,004 filed May 31, 2002. The entiredisclosure of all these documents is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This disclosure relates to the field of residue detection. Inparticular, to the automatic detecting of residues of substances presentin letter mail while the mail is in a postal facility.

2. Description of the Related Art

Since the use of Anthrax in the United States Mail in October 2001,government organizations have becoming increasingly interested indetecting dangerous substances such as microorganisms, chemicals, orbiological warfare agents which could be distributed through the mailsystem to promote the agenda of a terrorist organization. As the postalservice and mail delivery is a virtually universal service touching thelives of almost all people throughout the United States and many morethroughout the world, the postal service presents a potentiallylimitless distribution network for a terrorist group to utilize.Further, by the time a letter or package has reached the finaldestination, it has often been handled by many individuals, some of whommay not be known without a lengthy investigation. Any or all of theseindividuals may have been exposed to the substance and could be affectedwithout rapid medical response. Further, in the case of a contagioussubstance, trying to quarantine those exposed prior to the contagionbecoming epidemic may be virtually impossible.

October 2001 was not the first use of the mail for terrorist acts. Mailbombs and even dangerous pranks were common long before the mail wasused as a method for distributing a biological warfare agent. Inaddition to purposeful terrorist acts, sometimes dangerous substancesare shipped in the mails innocently or for other purposes. Dangeroussubstances may be shipped by a person who simply does not think of theconsequences or the mail may be utilized for other illicit acts such asdrug trafficking.

In order to allow the mail to be secure to parties using the mail systemfor legitimate purposes, mail is sealed and the contents are generallyinaccessible to postal workers. This confidentiality is necessary asmuch of the mail includes confidential information such as financialinformation and the like and mail which was open could lead to theft offinancial information and other important information. At the same time,the sealing of mail can make it difficult for a contaminant to bedetected until the mail has reached its prescribed destination and beenunleashed.

For the most part, there are no systems designed to screen mail,particularly letters and flats, for contaminants. Existing systems areoften limited to large boxes and packages and can only screen for itemswhich can show up on x-ray or similar scanners. These systems, whileoften effective for detecting bombs, are generally unable to detectpowders, liquids, or similar substances which are unlikely to show up onthe scans. Oftentimes, the defense to using the mails for terrorist actsis simply to expose the mail to powerful radiation or otherdecontaminants in the hopes of neutralizing any biologicals present, butthis cannot protect against chemical agents and can also damage maildocuments. Further, such irradiation is often performed after mail issorted to protect the recipient, but there may have been many exposedprior to this step,

SUMMARY

For these and other reasons known to those of ordinary skill in the art,described herein are systems and methods for the detection of residuesof a substance placed within letters and other “flats” of mail. Thesystem is principally designed to be included as part of Dual Pass RoughCull System (DPRCS) for the detection of the contaminant when it firstenters a mail facility. The system is particularly directed to detectingthe residue of a substance or a carrier for a substance but may alsodetect the substance itself This system includes letter handlingstructures comprising two arrays of pinch rollers in the aerosol chamberto decrease the likelihood of damage to mail pieces.

Described herein, in an embodiment, is a residue collection system forcollecting residues from the mails, they system comprising: an aerosolchamber including: an internal area; at least two arrays of pinchrollers, each of said arrays comprising two sets of pinch rollers, eacharray of pinch rollers being capable of compressing a mail piece locatedwithin said internal area, and an intake plenum, said intake plenumbeing capable of collecting air from said internal area and beinglocated between any two of said at least two arrays of pinch rollers;wherein said mail piece passes through a first array of said at leasttwo arrays of pinch rollers, said first array of pinch rollerscompressing said mail piece so as to force out some internal air fromwithin said mail piece as said mail piece passes through; wherein saidmail piece passes through a second array of said at least two arrays ofpinch rollers, said second array of pinch rollers also compressing saidmail piece so as to force out additional air from within said mail pieceas said mail piece passes through; wherein at least one of said someinternal air and said additional air includes a residue of a substancepresent in said mail piece; wherein said intake plenum can take in atleast a portion of said additional air including said residue from saidinternal area; and wherein said intake plenum can supply said additionalair including said residue to a detection system capable of detectingsaid residue.

In an embodiment, the residue collection system further comprises asegregation component arranged prior to said aerosol chamber in a mailstream, said segregation component serving to provide said mail piece tosaid aerosol chamber which may include a cull conveyor or a delayeringconveyor. The delayering conveyor may be located after said cullconveyor, may utilize velocity differential separation relative to saidcull conveyor or may utilize gravity separation.

In another embodiment of the residue collection system the residue isindicative of a Chemical or Biological Warfare Agent (CBWA) beingpresent in said mail piece or the residue collection system may be partof a Dual Pass Rough Cull System (DPRCS).

In another embodiment of the residue collection system each of said setsof pinch rollers comprises a plurality of disks. One of said sets ofpinch rollers in each of said at least two arrays of pinch rollers maybe a drive pinch roller and the other is an idler pinch roller at leastone which may constructed of a flexible material such as, but notlimited to, rubber. At least one of said drive pinch roller and idlerpinch roller may have a width between 0.75 and 1.25 inches, morepreferably of about 1 inch. In an embodiment, said disks in a first ofsaid arrays are arranged farther apart than said disks in a second ofsaid arrays, which may be touching each other, and the mail piece maypass through said first array before passing through said second array.

In a still further embodiment of the residue collection system the airpasses through a cyclonic separator system before reaching saiddetector. The mail piece may also be a letter or a flat.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides a simplified drawing of an embodiment of a lettercollection mail processing facility.

FIG. 2 provides a graph showing an embodiment of how different types ofcosts are saved by earlier detection of a contaminated mail piece.

FIG. 3 provides a side view of an embodiment of a Dual Pass Rough CullSystem (DPRCS) of the prior art showing the section which is modified byan embodiment of the invention.

FIG. 4. provides a side view of an embodiment of a modification made tothe section indicated in FIG. 3 that provides the principal structure ofa Residue Collection Module (RCM).

FIG. 5 provides a perspective view of an embodiment of a portion of theRCM of FIG.4 specifically showing an embodiment of the cull conveyorsand delayering conveyors.

FIG. 6 provides a drawing of how velocity differential separation canwork for two layered objects

FIG. 7 provides a side cut-away view of an embodiment of a portion ofthe RCM of FIG. 4 specifically showing an embodiment of the aerosolchambers and waterfall in their closed, operating position.

FIG. 8 provides a side, cut-away, view of an embodiment of one of theaerosol chambers of FIG. 7.

FIG. 9 provides a perspective view of a portion of the aerosol chamberof FIG. 8 particularly showing the arrangement of the drive pinchroller,

FIG. 10 provides a perspective view of a portion of the aerosol chamberof FIG. 8 particularly showing the arrangement of the idler pinchroller.

FIG. 11 provides two views (one front and one side) of an embodiment ofthe air flow through the aerosol chamber of FIG. 8.

FIG. 12 provides a side cut-away view of an embodiment of a portion ofthe RCM of FIG. 4 specifically showing an embodiment of the aerosolchambers and waterfall in their open, maintenance position.

FIG. 13 provides a schematic diagram of an embodiment of an air handlingsystem for use with the aerosol chambers of FIG. 8

FIGS. 14-19 provides an embodiment of an RCM and air handling systemforming a portion of an embodiment of a DPRCS.

FIGS. 20-22 provide various views of another embodiment of an aerosolchamber as shown in FIG. 7. This embodiment has two arrays of pinchrollers.

DESCRIPTION OF PREFERRED EMBODIMENT(S)

While the embodiments described below discuss residue collection moduleswhich are designed to detect Chemical and/or Biological Warfare Agents(CBWAs), one of ordinary skill in the art would understand how theprinciples, methods and designs disclosed herein can be incorporated todetect other materials in the mail. This can include, but is not limitedto, explosive residues, chemicals, drugs, or microorganisms.

The systems and methods discussed will also be primarily discussed ascollecting a residue of a substance. For the purposes of thisdisclosure, a residue is considered to be a small amount of a substance,or a material associated with that substance, generally clinging to theouter surface of the mail from the actions of placing the substance inthe envelope. This may exist because the substance has passed over asurface and a small amount of it has been transferred to the surface(via surface tension), has been transferred from fingers or other toolshandling the envelope, or may be that a small amount aerosolized in theenvelope. A residue can also comprise a small amount of the substance,or material associated with that substance, which can be aerosolized andremoved from the envelope by compressing the envelope. A residue may notdirectly be the substance whose detection is desired, but may be asubstance indicative of the presence of the first substance. Forinstance, the substance or residue may be, but is not limited to, achemical binder used to particulate a gaseous chemical, or may be asubstrate on which a biological is placed.

Further, while the embodiments discussed below are principally for usein conjunction with a Dual Pass Rough Cull System (DPRCS) in the mailservice, one of ordinary skill in the art would understand that thesystem and methods could be used elsewhere in the mail sorting anddistribution process. The inclusion in the DPRCS is instead an exemplaryembodiment, but one which is generally preferred as it can allow forearlier detection and less exposure than utilizing similar systems andmethods elsewhere in the mail distribution process.

With the possibility of over 100 CBWAs that a postal service may wish toscreen for, and the myriad of sensor systems presently in development todetect these agents, this disclosure is primarily directed towardsdevices and methods for collecting a sample of substances in the mailwithout having to open the mail and without having to expose the mail topotentially dangerous or damaging counter measures which could damagelegitimate contents. The number and type of substance detectors useddepends upon each detector's capability and the degree of redundancydesired. Extensive research has taken place in the scientific communityto develop sensors, which will quickly detect CBWAs or other substancesof interest in the air or in water. Sensors are available to identifyharmful biological agents as well as chemical ones. Sensor's forairborne agents are capable of measuring CBWAs at parts per trillion.Depending upon the sensor technology, analysis can be accomplishedanywhere from an hour to near “real time.” For the purposes of thisdisclosure the exact type or number of detectors used to detect theparticular substance is not important as the residue collection systemof the invention is instead focused to obtaining a sample of a residue(if present) on a mail piece and providing it to the detector so thatthe detector detects that the substance is present, not with how thedetector determines if there is the substance present.

To minimize exposure to employees and reduce cost, a contaminated letteris preferably identified early in the mail processing cycle. The reasonfor this is that the further the contaminated mail is allowed to travelbefore it is detected, the more it spreads throughout the facility andthe more people who are potentially exposed to it. In the case of acommunicable disease or microorganism, for example, as the number ofpeople exposed increases, the likelihood of being able to contain anoutbreak can decrease drastically,

FIG. 1 provides a general overview of an embodiment of a mail collectionfacility Mail enters the facility in hampers (101) or (103) which aresimply large bags or other containers of mail which have been created atthe facility or have been transferred to the facility The hampers (101)and (103) are then dumped into the corresponding Dull Pass Rough CullSystem (DPRCS) (105) or (107). At this time, the mail from the hamper(which is from a determinable location) is still together and hasgenerally not come into contact with any mail not originally in the samehamper (101) or (103). As it passes through the DPRCS (105) and/or(107), thicks (packages or boxes usually) are separated out from theletters and flats (large but thin envelopes usually). After the DPRCS(105) and (107), the flats and letters are mixed together andconsolidated. A flats takeaway sorter (113) then removes the flats fromthe mail stream leaving the letters. The letters are spread out among anumber of surge and transport conveyor's as they enter the Loose MailFeed System (109). The letters are further spread out as they reach theAdvanced Facer Canceller System (AFCS) (111) and ultimately the sortingmachines (Not Shown) During this process, the letters, instead of beingseparated by their pickup points as they are when the process starts,are slowly organized by their destinations and become more and moreintermingled.

As the mail spreads out, not only do the number of sensing systems thatwould be needed to detect a contaminant increase dramatically, butshould a contaminated mailpiece be found, the number of mail processingsystems that must be decontaminated also rises dramatically as does thenumber of employees exposed to the potentially lethal agent. Further, itcan become harder and harder to localize the source of the contaminantas the source may have contaminated many other mail pieces that it wasin contact with. It is therefore desirable to detect the contaminationat the earliest possible opportunity For collection mail, the preferableopportunity for detection is at the DPRCS and therefore in the preferredembodiment the systems and methods discussed herein are designed to belocated there.

If the CBWA is detected at the DPRCS (101) or (103), less than 100 feetof conveyor in one system is contaminated. However, if the CBWA is notdetected until the AFCS (111) there can be over 1000 feet of conveyorand anywhere from 3 to 10 or more pieces of equipment may becontaminated. The time to decontaminate the facility and the associatedcost impact dramatically increases with this later detection.

From an acquisition cost and maintenance, cost perspective, earlydetection at the DPRCS can result in a 3:1 reduction in the number ofdetectors. This is a result of the DPRCS being capable of processing120,000 or more mailpieces per hour while an AFCS can only process36,000 letters per hour The initial acquisition cost reduction can bevery significant when presently “real-time” CBWA detectors typicallycost between $100,000 and $275,000 each just for the basicinstrumentation alone.

From a decontamination point of view, the DPRCS is the preferred placeto detect any hazardous substance. Isolation and appropriatedecontamination procedures can be invoked prior to the mail spreadingout and contaminating other pieces of postal equipment. The variousincreases in costs of detecting as it occurs later in the process isillustrated graphically in FIG. 2.

The following sections describe an embodiment of a Residue CollectionModule (RCM) which comprises a device which can be retrofitted into anexisting DPRCS, or can be built into a new DPRCS for the purposes ofdetecting residues associated with various substances of interest (inparticular CBWAs) within mail and particularly within flats or letters.One of ordinary skill in the art would understand that the systems,devices, methods and techniques discussed below could be incorporatedelsewhere in the postal facility. Such an installation may simply resultin increased cost and/or redundancy, and/or may be used for thedetection of other substances.

The primary purpose of the RCM is to safely extract and aerosolize aresidue associated with a substance or of the substance itself, whichmay be within, or on the surface of, mail pieces that pass through theDPRCS. The aerosolized mixture is then delivered to a selected detectionsystem for subsequent analysis to detect the substance associated withthe residue. The aerosolized mixture which is produced by the RCM iscompatible with a wide variety of detection methods as are known tothose of ordinary skill in the art, but is preferably suited for thosethat use an impaction process or other similar method for concentratingan aerosol sample down onto a solid substrate or into a liquid solution.

In the depicted embodiments, the RCM (701) is part of and included as amodification for a DPRCS (400) such as those known to those of ordinaryskill in the art. FIG. 3 illustrates the portion (700) of a prior artDPRCS (400), which may be modified during the RCM (701) installation inan embodiment of the invention. The portion that is modified generallycontains the cull conveyors (406) and the waterfall assembly (408). FIG.4 provides an illustration of an embodiment of an RCM (701) which mayreplace the portion (700) of the DPRCS (400) in FIG. 3. In essence, themodification consists of replacing the indicated portion (700) of FIG. 3with the RCM (701) shown in FIG. 4. There are some control modificationsand an air handling system that are not shown in this FIG. 4, but FIG. 4shows the principal components of the RCM (701).

The RCM (701) generally maintains the same key functional features ofthe DPRCS cull conveyors (406) and waterfall assembly (408) while addingthe residue collection aspects Consequently, the RCM (701) need notdecrease any of the critical performance metrics of the current DPRCSdesign. In effect, the RCM (701), when combined with a compatibledetection system, can provide the same functions of an existing DPRCSwhile providing a high level of safety for the loose mail collectionoperation and the entire facility as well.

The RCM (701) depicted in FIG. 4 includes components which may beeliminated in some embodiments of the invention. In particular, the RCM(701) of FIG. 4 includes two major components. The first of thesecomponents is the segregation component (703) which provides for lettersto be provided to the second component which is the actual collectionsystem component (800). The segregation component (703) may beeliminated or can have numerous other designs in alternative embodimentsso long as the letters are provided to the collection system component(800) in a manner that the collection system component (800) can actupon them and collect a sample from them. The segregation component(703) shown in the FIGS (particularly FIGS. 5 and 6) is thereforeintended to be exemplary.

Since the RCM (701), in an embodiment, is designed to be an integralpart of the DPRCS (400) sorting process, the operation of the RCM isbest understood in light of the entire DPRCS operation The followingdiscussion briefly summarizes the function of the various modules of theDPRCS, how they relate to the overall culling process of mail, and howthey relate to the residue extraction and aerosolization process. Thisdiscussion is best visualized in conjunction with FIGS. 3-7.

In an embodiment, the DPRCS input is a set of inclined conveyors thatare designed to receive mail from standard mail hampers and to deliverthis mail in a metered flow to the subsequent culling section Loosecollection mail is dumped from a hopper and enters the DPRCS (400) atthe input hopper conveyor (401) Here the mail is moved forward up aninclined conveyor belt where it is temporarily staged until it is calledfor by the reservoir (405) at the bottom of the next conveyordownstream. The rate of mail being delivered to this reservoir (405) isgenerally controlled by photocells (407) so that the level of mailwithin the reservoir (405) remains fairly constant. By doing this, theinput hopper conveyor (401) buffers the downstream operation from therather large fluctuations in mail flow caused by the dumping of mailhampers. This greatly enhances the effectiveness of the next processdownstream.

The next conveyor downstream from the input hopper conveyor (401) is themetering conveyor (403). The purpose of the metering conveyor (403) isto provide mail at a steady rate to the next process downstream. Aspreviously described, the input hopper conveyor (401) keeps thereservoir (405) at the bottom of the metering conveyor (403) at a steadylevel. The metering conveyor (403) pulls mail out from beneath the pileat the bottom of the conveyor. The mail that has been pulled out of thepile forms a layer of mail which slowly advances up the meteringconveyor (403).

To adjust for variations in the thickness of the mail layer, feelergauges (409) near the top of the metering conveyor (403) measure thethickness of the layer and adjust the speed of the metering conveyor(403) accordingly. The metering conveyor (403) will slow down for athicker layer of mail and will conversely speed up if the layer of mailshould thin out. In this manner, the flow of mail at the output end(top) of the metering conveyor (403) remains relatively constant. Theflow rate of mail exiting the metering conveyor (403) is operatorselectable. The maximum rate for the system is approximately 120,000mailpieces per hour. The RCM (701) may be designed to handle thismaximum mail flow rate.

As the mail drops from the output end of the metering conveyor (403),the mail is considered to enter the portion (700) of the DPRCS (400)which is replaced by the RCM (701). This would traditionally be theculling section. The RCM (701) as shown in FIG. 4 is comprised of threemajor subsections, their associated controls, and an air handlingsystem. The three major sections are the cull conveyors (500), thedelayering conveyors (600), and the collection system component (800).These sections are each described in detail in the subsequent paragraphsas is the air handling system (1100). These sections replace the cullconveyors (406) and waterfall (408) of the prior art DPRCS (400). As themail exits the DPRCS (400), it is placed on an edge conveyor (411) fortransport to the next machine as seen in FIG. 1.

When the RCM (701) is in place in the DPRCS (400), the mail from themetering conveyor (403) is first provided to the cull conveyors (500).The cull conveyors (500) are similar in design and may be identical infunction to the cull conveyors (406) of the present DPRCS (400). Theprincipal purpose of the cull conveyors (500) is to separate out thickmailpieces from the rest of the mail stream and to discharge them onto aseparate take-away conveyor which is not shown in the figures. FIG. 5provides an illustration of the cull conveyors (500) along with thedelayering conveyors (600) The cull conveyors (500) are the first set ofstacked conveyors. Each of the two cull conveyors (500) in the depictedembodiment comprises a smooth-top cotton belt, or similar conveyorsystem (503) and (505), with a counter-rotating cull drum (513) and(515) positioned above it. In the illustration, the conveyor motion isfrom left-to-right and into the figure as illustrated by the arrows.

The metering conveyor (403), described previously, feeds a steady flowof mail onto the top cull conveyor belt (503). The mail is transportedforward by the top cull belt (503) until it reaches the top cull drum(513). Mail pieces that are less than a predetermined thickness(generally 5/8 inch) pass beneath the top cull drum (513) Mail piecesthat are over the predetermined thickness are deflected by the top culldrum (513) and forced to the side opening (533) of the top cull conveyorbelt (503) where they are discharged through a chute (523) During thisprocess, some of the thinner mailpieces which are less than thepredetermined maximum are swept off of the top cull belt (503) alongwith the thicker mail pieces (generally due to the mail pieces beingstacked on top of each other as they come off the metering conveyor(403)). The mail discharged through chute (523) is discharged onto thebottom cull belt (505) where the process is repeated with the mailtraveling on the bottom cull belt (505) and thicker pieces beingdeflected by the lower cull drum (515), thus giving thinner mail piecesa second chance to re-enter the major mail stream (the stream of flatsand letters). Those pieces which are deflected off both the top and thebottom cull belts (503) and (505) are then discharged onto a “thicks”take-away conveyor (not shown, would be connected to the opening (525))where they are transported away from the DPRCS (400) to be processeddifferently. All of the mail, which passes beneath either of the twocull drums (515) or (525) (which comprises the vast majority of the mailcollected) is subsequently transported forward to have the residueextraction and aerosolization process performed thereon.

Although the cull conveyors (503) and (505) of the RCM (701) may befunctionally identical to those of the standard DPRCS (400), the overalllength of the conveyors is preferably shorter. This is done to providespace for the subsequent delayering operation to be described later. Theoriginal cull module (406) in the DPRCS is often approximately 151″ longThe RCM cull module (500) is preferably only about 86″ long. The reducedlength may be realized in an embodiment of the invention by reducingsome of the conveyor length both before and/or after the actual cullingprocess. All of the critical dimensions in regard to the cullingoperation, such as cull drum angle and relative position, can bemaintained so that the operation of the DPRCS (400) can remain the same.

There is however, one difference between the original cull conveyors(406) and the RCM cull conveyors (500) in the preferred embodiment Onthe original cull conveyors (406), the mail on the top conveyor isallowed to fall off the downstream end of the top conveyor (503) andonto the bottom cull conveyor (505). There it recombines with the mailthat is already on the bottom conveyor (505) to produce a single mailstream. In the RCM (701), the mail from these two conveyors (503) and(505) is preferably maintained separate, but it is not necessary. Aswill be described in the next section, this is beneficial for thesubsequent mail delayering process.

The output from each of the two cull conveyors (503) and (505) feedsdirectly onto an associated delayering conveyor (603) and (605). Thepurpose of the delayering conveyors (603) and (605) is to provide asingle layer (or a stream of generally single item thickness) ofnon-overlapped mail to each aerosol chamber (803) and (805) as discussedlater. During normal operation, the mail may arrive at the delayeringconveyors (603) and (605) in the form of overlapping “clumps” of mailwhere one flat of mail is at least partially over another flat of mail,but the thickness is still less than that allowed by the cull drums(513) and (515). In order to maximize the probability that a CBWA willbe extracted and aerosolized, these clumps of mail are preferably spreadout to form a single layer or close to a single layer of mail by theappropriate delayering conveyor (603) or (605).

The preferred embodiment uses two delayering conveyors (603) and (605)for spreading out the clumps of mail, one associated with each cullconveyor (503) and (505). The reason for this is that the cull conveyors(503) and (505) effectively already perform a preliminary delayering ofthe mail by spreading the mail out onto each of the two cull belts to athickness of ⅝″ or less. In the prior art DPRCS, the mail on the topbelt is then recombined with the mail on the bottom belt, thus defeatingthe partial delayering achieved by the action of the cull drums (513)and (515). By using two delayering conveyors (603) and (605) andinterfacing with the two cull belts (503) and (505) prior to therecombination point, the RCM (701) takes full advantage of the partialdelayering effect of the cull drums (513) and (515). In addition, byusing two stacked delayering conveyors (603) and (605) instead of justone, the RCM (701) doubles the total amount of available surface area onwhich to perform the final delayering process, thus greatly enhancingthe effectiveness of this operation.

The delayering conveyors (603) and (605) use two principal delayeringmethods in the depicted embodiment. The first of these methods isvelocity differential separation. This is primarily used at both theinput and the output of the delayering conveyors (603) and (605). Thesecond method is gravity separation which occurs over the entire lengthof the delayering conveyors (603) and (605).

The first method, velocity differential separation, is the process ofseparating the mailpieces by accelerating the lead mailpiece away fromthe mailpiece that is partially behind it to move them further apart.The speed of the cull conveyors (503) and (505) is preferably a firstspeed (V1) which in a preferred embodiment is approximately 148 feet perminute (FPM). The speed of the delayering conveyors is preferably set ata faster second speed (V2). The second speed (V2) is preferablyapproximately 52 FPM faster or around 200 FPM.

FIG. 6 provides an illustration of the velocity differential separationprocess. In FIG. 6A there is shown two overlapped pieces of mail (711)and (713) approaching the interface of the cull conveyor (503) and theassociated delayering conveyor (603). In FIG. 6B there is shown thefirst mailpiece (711) being fully engaged by the faster delayeringconveyor (603) and moving away from the second mail piece (713) that isstill under the influence of the slower cull conveyor (503) and gravity.FIG. 6C shows the separation effect on the two mailpieces (711) and(713) caused by the velocity differential at the interface.

While the interface between the cull conveyors (503) and (505) and thedelayering conveyors (603) and (605) provides for the primary velocitydifferential separation, the separation actually takes place at twodifferent locations. The first of these locations, is the input end ofthe delayering conveyors (603) and (605) at their interface with thecull conveyors (503) and (505) as discussed in FIG. 6. The secondlocation is at the output end of the delayering conveyors (603) and(605) at their interface to the chutes (813) and (815) that feed theaerosol chambers (803) and (805) As the mailpieces fall down the chutes(803) and (805) under the influence of gravity, they are acceleratedaway from those mailpieces that are still in contact with the delayeringconveyor (603) or (605) (which are moving at the speed of the delayeringconveyor (603) or (605)) Although the mechanism is somewhat different(powered motion vs gravity), the principal is still the same.

The second method of delayering is gravity separation. The delayeringconveyors (603) and (605) are preferably inclined at a predeterminedangle to the surface of the earth. This angle is preferablyapproximately 30° or greater from the horizontal. The belt material ofthe delayering conveyors (603) and (605) is further preferably made ofdiamond wedge belting or of another high-friction belting material. Mailpieces which are in contact with the conveyor belt are pulled forward upthe incline because of the fiction. Mail pieces which are laying on topof other mail pieces fall backwards under the influence of gravity dueto the low coefficient of friction between mail pieces, especially whencompared to the interface of the belting to the mail piece. The top mailpieces slide back until they come in contact with enough of the beltsurface that they too are pulled forward by the belt surface. The netresult is that the mail on the bottom of the layered stream is pulledforward while the mail on the top of the layered stream is retarded dueto the force of gravity.

The output of the delayering process therefore is a stream of mailpreferably spread across the 4′ width of the delayering conveyor so thatno two mailpieces are entirely covering one another. This is desired forthe aerosolization process, which is to follow, because it is preferableto get access to most of the surface area of each mail piece that passesthrough the aerosol chambers (803) and (805). The delayering conveyors(603) and (605) generally help to improve the efficiency and detectionability of the detector (1109) However, in an alternative embodiment,the mail may be provided to the collection system component (800) by anymethod or system known to those of ordinary skill in the art, including,but not limited to, using the prior existing cull conveyors (406) ofDPRCS (400).

The primary purpose of the aerosol chambers (803) and (805) and thecollection system component (800) of the RCM (701) is to extract aportion of any residue of a substance on the outside of the mail pieceas well as a portion of any residue of a substance from inside the mailpiece, aerosolize this residue, and deliver this aerosolized mixture toa detection system for analysis. Since the mail upon exiting thedelayering conveyors (603) and (605) produces two separate mail paths inthe depicted embodiment, two separate aerosol chambers (803) and (805)are also utilized within the collection system component (800) of RCM(701).

FIGS. 7 through 12 and 17 through 22 provide illustrations of differentembodiments of the collection system component (800) and the aerosolchambers (803) and (805) included therein. This collection systemcomponent (800), effectively comprises the portion of the system whichis used to collect the residues. The previously discussed systems areprincipally designed to organize the mail to be provided to thecollection system component (800) in a manner allowing for moreefficient operation.

In operation, mail pieces are discharged from each of the two delayeringconveyors (603) and (605) and proceed down separate gravity feed chutes(813) and (815) to their respective aerosol chambers (803) and (805)After aerosolization, the two separate mail paths are merged togetherand the mail generally drops onto the edge conveyor (411) where it istaken to the next sorting machine. After reaching the edge conveyor(411), the residue collection process is generally completed.

A more detailed side view of an embodiment of one of the aerosolchambers (in this case chamber (803) but chamber (805) is identical) isshown in FIG. 8. The aerosol chamber (803) comprises two sets of pinchrollers (901) and (911), a set of air intake plenums (903) and (913),and a set of guides (905) which direct the mail through the chamber(803).

This particular view also shows the chamber (803) with a fairly thick(but flat) mail piece (809) inside of it to illustrate its capacity tohandle relatively large flats. The mail piece (809) enters the aerosolchamber (803) from the top (907) after coming down the waterfall chute(813). A set of opposing guides (905) funnel the mail piece (809) pastthe two opposing intake plenums (903) and (913) which are generallydesigned so as to draw air from across the entire width of the internalarea (915) of the chamber (803). As the air is drawing across theexterior of the mail piece (809) any residue on the exterior of the mailpiece (809) is at least partially aerosolized and carried into one ofthe two air intake plenums (903).

The mail piece (809) then travels between two sets of motorized pinchrollers (901) and (911) which squeeze the mail piece (809) as it passesthrough. FIG. 8 shows the lead edge of the mail piece (809) justentering the pinch rollers (901) and (911). The squeezing action of thepinch rollers forces out some of the air from within the mail piece(809). A portion of any residue within the mail piece (809) is alsogenerally forced out with the release of this air. Any extracted residuethat is released from the inside of the mail piece (809) aerosolizes inthe internal area (915) of the chamber (803) and is usually drawn intothe intake plenums (903) and/or (913).

The aerosol chamber (803) is preferably held at negative pressure bydrawing air into the intake plenums (903) and (913) so that anyaerosolized residue from the mail piece (809) is left behind in theinternal area (915) of the chamber (803) as the mail piece (809)continues through the pinch rollers (901) and (911) and is ejected outthe bottom (917) of the aerosol chamber (803) and into the edge conveyor(411).

Now that the operation of the aerosol chamber (803) has been brieflydescribed, a more complete description of the structure can be made. Asmentioned previously, an embodiment of the aerosol chamber (803) iscomprised of two sets of pinch rollers (901) and (911) forming a singlearray of pinch rollers, a set of air intake plenums (903) and (913), anda set of guides (905). These items are preferably enclosed within ahousing (921) which may be constructed of sheet metal or anothersuitable material. The intake plenums (903) and (913) may be commercialoff-the-shelf (COTS) items that come in a standard 4′ length and areavailable currently. Each intake plenum (903) or (913) is basically ahollow tube with a slit that runs the entire length of the tube on oneside. Air is drawn into the slit and exits out one end of the intakeplenum. Air exiting the intake plenum (903) or (913) enters the airhandling system (1100) which shall be described later in conjunctionwith FIG. 13.

Referring again to the embodiment shown in FIG. 8, the sets of pinchrollers (901) and (911) are each slightly different. The left pinchroller or drive pinch roller (911) is preferably a motor driven rollersupported by bearings mounted to the air chamber housing (921). It ispreferably approximately 5″ to 6″ in diameter. The tangential velocityof the drive pinch roller (911) is preferably set somewhat greater thanthe speed of the mail entering the chamber (803) in order to ensure thatconsecutive mail pieces remain separated during the aerosolizationprocess. Opposite drive roller (911) is an idler pinch roller (901)which may be spring loaded and will generally be free-wheeling asopposed to motorized. This is shown on the right-hand side of FIG. 8 andin FIG. 10. The idler pinch roller (901) not only acts as the opposingpinch roller required to drive the mail piece (809) forward, but it alsoserves as the mechanism for squeezing the air out of the mail piece(809) to release the residue from within the mail piece (809). Like thedrive pinch roller (911), the idler pinch roller (901) is alsopreferably 5″ in diameter. The large diameters on each set of pinchrollers (901) and (911) make it easy for even the thickest mailpieces topass through unobstructed. In another embodiment, these two rollers(901) and (911) would both be mounted by bearings to the air chamberhousing (921) and the pinching action would be supplied by the design ofa rubber covering on each roller (901) and (911).

A 3D cutaway view of the drive side of the chamber (803) is shown inFIG, 9. Shown in FIG. 9 is intake plenum (913) as well as an embodimentof the drive pinch roller (911) The drive pinch roller (911) comprisesof a motor driven shaft (1011), which extends the width of the chamber(803). The shaft (1011) may have a number of disks (1013) mounted on itor may have grooves cut into it. Each disk will preferably be from about0.75 to about 1.25 inches in width, more preferably about an inch inwidth This can allow the mail guides (905) to pass between the disks.The grooves between the disks (1013) also provide channels for air topass through the drive pinch roller (911) as it is drawn toward theintake plenum (913).

A 3D cutaway view of an embodiment of the idler pinch roller (901) ofthe chamber (803) is shown in FIG. 10. Also, shown in the FIG. 10 is theother intake plenum (903). The idle rollers (1003) match up with thecorresponding disks (1013) on the drive roller (911). Each idle roller(1003) may have its own independent suspension to ensure that pieces ofvarying thickness traveling through the unit side-by-side all getsqueezed with generally the same amount of pressure or they may bemounted on the same suspension system. The idle rollers (1003) arepreferably placed on centers no greater than 1.5″ apart in order toensure that even the smallest mailpiece shall have at least one pair ofidle rollers (1003) squeezing it.

While this embodiment provides for idle rollers that are spring-loadedso that each mail piece is squeezed even if mail pieces of differentthickness pass through side by side, this is not the only way toaccomplish effective squeezing. In an alternative embodiment either thedrive rollers (911), idle rollers (1003) or both may be manufactured ofa resiliently flexible materials such as rubber or flexible plastic. Inthis case the rollers themselves may compress as the mail piece passestherethrough using their flexibility instead of a specific spring loadedarrangement. This may act in place of, or in addition to, the rollersbeing spring mounted to provide for effective compression.

Another feature of the aerosol chamber (803) is the guides (905)themselves. These are best illustrated by the side view of the chambergiven in FIG. 8. The guides (905) are preferably constructed of sheetmetal and form a two-sided funnel to guide the mail piece (809) into theproper orientation and between the pinch rollers (901) and (911). In oneembodiment, the guides (905) extend down to a point immediately abovethe intake plenums (903) and (913). At this point there is an opening(usually about 1″ wide) to allow the air in the mail flow to be drawninto the intake plenums (903) and (913). After the opening, a new set ofguides (905) continue forward to the pinch rollers (901) and (911). Herethe guides (905) may have fingers cut into them so that they can reachthrough the spaces within the pinch rollers (901) and (911) and passthrough to the other side. The guide fingers are generally situatedbelow the level of the pinch rollers (901) and (911) so as not tointerfere with the pinching operation. The guide fingers then extendbeyond the pinch rollers (901) and (911) a short distance to guide mailpieces through the bottom (917) of the chamber (803).

A better appreciation of the guides (905) and the effect they can haveon guiding the airflow within the chamber (803) is illustrated in FIGS.11A and 11B. This simplified figure shows, as FIG. 11A, a side view ofthe chamber (803) including the air flow, and, as FIG. 11B, a front viewof the chamber (803) including the air flow. A mail piece (809) passesdown the internal area (915) formed by the guides (905), through thepinch rollers (901) and (911), and out the bottom end (917) of thechamber (803). The air travels up the internal area (915) between thepinch rollers (901) and (911) until it reaches the intake plenums (903)and (913). This is shown by the arrows in FIG. 11. The air will oftenmove in a generally laminar flow so that air flows over both the majorexterior surfaces of the envelope and generally fills the internal area(915). Further, the flow will be generally from the pinch rollers (901)and (911) to the intake plenums (903) and (913) to prevent residuereleased from escaping out the bottom (917) of the chamber (803).

In an embodiment, each of the two aerosol chambers (803) may open up formaintenance and jam clearing purposes. An illustration of an embodimentwhere a clam shell opening is used is shown in FIG. 12 and FIGS. 17-19.

FIGS. 20-22 provide for another embodiment of aerosol chambers (803) and(805). This embodiment provides for two arrays (1921) and (1931) each oftwo sets of pinch rollers instead of the single array used in theembodiment of FIGS. 8-11. Each array (1921) and (1931) comprises twosets (1901) and (1911) of pinch rollers corresponding to the two sets(901) and (911). Further the intake plenum (903) has been moved so as tobe below array (1921) and above array (1931). The two array(s) of pinchrollers (1921) and (1931) are particularly useful because of theirability to compress the mail pieces at a slower pace than when there isa single array of pinch rollers. Further, the second set of pinchrollers (1931) may be arranged so that the disks are closer together toprovide for more pinching action in this embodiment. Guides (905) andother structures discussed in conjunction with the embodiment of FIGS.8-11 may be included in a similar fashion in this embodiment, or may beeliminated.

The first array of pinch rollers (1921) provides for some squeezing ofthe mail piece which can result in residues being ejected. In anembodiment, the first array of pinch rollers may be of similar design tothe single array discussed in conjunction with FIG. 8. Once through thisfirst array of pinch rollers (1921). The mail piece, in the depictedembodiment of FIGS. 20-22 then passes the intake plenum and reaches thesecond array of pinch rollers (1931), which again squeeze the mail pieceto attempt to release any residue which may be present. This secondarray of pinch rollers (1931) will generally be arranged to squeezeadditional air from the mail piece. The mail piece then passes throughthe bottom of the aerosol chamber (803) or (805) to the edge conveyor asdiscussed above.

The two array (1921) and (1931) arrangement provides for some benefitsover the single array shown in FIGS. 8-11. In particular, because themail piece is squeezed twice, the first squeezing action can be lessthan the second with the two squeezing actions can combine to safelysqueeze out more air than can be accomplished in the single arrayembodiment.

If the mail piece is squeezed too quickly as can occur when trying toget sufficient air out of the mail piece in a single squeezingoperation, the mail piece can burst as the air being pushed out of themail piece cannot escape fast enough through existing openings andpressure will cause fractures in the paper. To avoid the burstingproblem, less air may be squeezed out which could potentially allow atrace residue to be undetected. The double pinch roller arrayarrangement of FIGS. 20-22 allows for increased total squeezing pressureat the end of the aerosol chamber (803) or (805) to be provided throughtwo separate squeezing steps resulting in smaller incremental pressuresbeing applied to the mail piece, which, in turn, helps to avoidbursting. In this way, the incremental change on each piece of mailthrough the aerosol chamber (803) or (805) is less than with a singleroller design for the same total pressure. The differential incurred bythe mail piece is between the split to two different arrays (1921) and(1931) making each differential less. In particular, if only a singlearray of rollers is used, all the air is squeezed out at once. If twoarrays are used, a lesser percentage of air may be squeezed out by thefirst array, with the remainder squeezed out in the second array.

A single array of pinch rollers can also prevent an undesirable jamsituation. When the individual rollers are constructed of flexiblematerial, as discussed previously, smaller mail pieces compressed intothe rollers can adhere to the rollers' external surfaces. As the mailpiece is ejected from the array of rollers, the mail piece may notdischarge from the rollers, but may continue to rotate about the rollerit is adhered to. This can drive the mail piece into mechanisms orsupports for the array damaging mail and possibly jamming the machine.The rate of adherence will generally increase as the pressure applied bythe array increases.

The embodiment of FIGS. 20-22 also provides for a different location ofthe intake plenum (903). In this embodiment, the intake plenum (903) islocated between the two arrays of pinch rollers (1921) and (1931),particularly being placed immediately above the second array (1931) inthe depicted embodiment. The placement of the plenum (903) between thetwo arrays of pinch rollers (1921) and (1931) serves multiple purposes.In the first instance, the plenum (903) generally maintains a negativepressure in the aerosol chamber (803) or (805) between the two arrays ofpinch rollers (1921) and (1931). Therefore, particulates released byboth arrays of pinch rollers (1921) and (1931) will be pulled toward theplenum (903) (generally between the rollers of the first array (1921) ifreleased by the first array (1921)). This arrangement is useful as thesecond array of pinch rollers (1931) is preferably arranged so as tohave little to no space between the rollers in the array providing forlittle chance for air to escape and contaminants to reach thesurrounding atmosphere.

In particular, as a mail piece passes through the first array of rollers(1921), the compression of the mail piece will generally release onlyeasier to release particles from the mail piece and will not eject allthe air from the mail piece. This air will be ejected above the upperarray of pinch rollers (1921) and will be sucked downward into theplenum (903) by the negative pressure created by the plenum (903). Theparticulates and air released will generally flow between the rollers onthe array (1921), as discussed in conjunction with FIG. 11, and towardthe plenum (903).

Further, the initial pinching action of the first array (1921) (or there-expansion after pinching) may serve to disturb particulates in themail piece stirring them into the air in the mail piece even if they arenot ejected. The mail piece is then further exposed to the generallynegative pressure of the center section. The negative pressure willgenerally cause particles on the mail piece, or those in the mail piecewhich were stirred, to be pulled from the mail piece.

As the mail piece goes through the transition space between the twoarrays of pinch rollers (1921) and (1931), it has already been partiallyflattened by its passage through the first array of pinch rollers(1921). However, as it has not been completely compressed against thefirst array of pinch rollers (1921) it is unlikely that the mail piecewill adhere to the surface of the rollers as can be the case duringstrong fast compression. Because the compression pressure can be lessthan in the single array, the mail piece will instead generally continueon a linear track between the two arrays of pinch rollers (1921) and(1931) as the pressure is not sufficient to cause adherence.

The second array of pinch rollers (1931) will impart additionalsqueezing on the mail piece forcing more internal air out of the mailpiece and toward the intake plenum (903). This additional squeezing willgenerally apply more pressure to the mail piece than what was applied bythe first array, although, in an alternative embodiment, similarpressure (or less pressure) may be used as any of these still results inadditional compression. The use of the phrase “additional squeezing” isto refer to the fact that the letter is squeezed a second time, notnecessarily that more pressure is used. This additional squeezing caneject more smaller particles (which will often be of more interest) tothe intake plenum (903) from the inside of the mail piece or ejectparticles aerosolized in the first squeezing but not ejected. This isparticularly valuable if the residue of interest is of small size inparticulate form in the mail piece.

The second array of pinch rollers (1931) will generally comprise rollersthat are significantly closer together that in the first array of pinchrollers (1921). This design is preferred as it allows for additional airto be compressed from the mail piece, hopefully approaching all of theair originally in the mail piece being squeezed out. So as to supplysufficient pressure, the second array of pinch rollers (1931) willgenerally comprise rollers spaced closer together than in the firstarray of pinch rollers (1921). In an embodiment, there is no spacebetween the rollers which are arranged directly side by side. Therollers will however, still be spring mounted, or may be of compressiblematerial, to allow for mail pieces of different sizes to passsimultaneously side by side and still be squeezed. While this array mayactually squeeze a net of more air from the mail piece than would besqueezed in a single array case, because this array is second, the mailpiece has already been partially compressed and is therefore less likelyto adhere or suffer from bursting.

The two array pinch roller (1901) and (1903) embodiment of aerosolchambers (803) and (805) therefore will generally provide for animproved sampling of residues, as well as for an improved mail handlingability over that of the single array pinch roller system shown in FIGS.8-11 by decreasing the number and severity of damaged mail pieces byadherence or bursting and by decreasing the likelihood of a jam from amail piece adhering to an array of pinch rollers. The decrease in damageis generally attributable to a decrease in incremental pressure withouthaving to decrease total pressure applied. As would be apparent to oneof ordinary skill in the art, however, either embodiment of aerosolchamber (803) or (805) may be used in the system depending on thecharacteristics desired. Still further, in another embodiment, more thantwo arrays of pinch rollers may be used in each aerosol chamber (803)and (805). Such a larger number of arrays can provide for even smallerincremental changes.

The air collected from the mail piece (809) in the input plenums (903)and (913) (which contains the aerosolized particles of the residue ifone is present) is then preferably removed from the input plenums (903)and (913) and the main body of the RCM (701) by an air handling system(1100) which provides the air to the selected detector (1109) forevaluation and detection of the residue. FIG. 13 is a schematic diagramof an embodiment of an air handling system (1100) which may beassociated with one or both of the aerosol chambers (803) and (805) andwith any embodiment of aerosol chambers. For clarity purposes, theembodiment of FIG. 13 will be discussed as attached to chamber (803) andto only one intake plenum (903). One of ordinary skill in the art wouldunderstand how the air flow from related components is generally similarto this case regardless of how the air handling system (1100) isattached.

In the depicted embodiment of the air handling system (1100), airentering the intake plenum (903) is routed through duct work or otherair transport devices (1101) and delivered to a flow cyclonic separatorsystem (1103). The design of the cyclonic separator system (1103)preferably operates in accordance with systems and methods described inU.S. Provisional Patent Appln. Ser. No. 60/560,122 the entire disclosureof which is herein incorporated by reference. However, one of ordinaryskill in the art would understand how other cyclonic separator systemscould be used. The cyclonic separator system (1103) is designed toconcentrate particles of a size of interest corresponding to the desiredresidues (preferably 0.8 micron and larger particles). Particles of thesize of interest are sent down a flow duct (1105) and delivered in anaerosolized form through to a detector system (1109). The detectorsystem (1109) preferably operates at a flow rate of 400 to 450 litersper minute but the air handling system (1100) can accommodate detectorsystems (1109) utilizing flow rates other than this.

Particulates not of the specified interest area, are cycled through aflow duct (1107) and exhausted (1113). The blower (1111) helps to pullthe air from the chamber (803) into the air handling system (1100). Theexhausted air may be returned to the surrounding air, or may be filteredand/or neutralized and reused in the system, or disposed of.

In another embodiment, the air-handling system (1100) would not use thecyclonic separator system (1103) but instead would duct the air from theintake plenum (903) directly to the detector system (1109). Thisair-handling system (1100) may be employed if the air flow rate andsensitivity of the detector system (903) allowed the use of such asystem.

The output of the RCM (701) preferably interfaces with the input of theedging conveyor (411). The type of mail and the associated throughputrate through this unit may be the same as from the unmodified DPRCS(400). The mail then exits the DPRCS (400), passes through the flatstakeaway sorter (113) and enters into the loose mail processing system(109) as was accomplished in the prior art.

In order to minimize the floor space required for the RCM (701), thecontrols as well as the air handling system (1100) for the RCM (701) maybe located in the area beneath the delayering conveyor (600). The sizeof the RCM (701) modification is preferably designed to be of generallythe same length as the cull conveyor (406) and the waterfall assembly(408) of a traditional DPRCS (400), which it replaces or retrofits.Therefore, the RCM (701) modification preferably does not addsignificantly to the overall footprint of the DPRCS (400).

To provide a higher degree of safety, in an embodiment of the invention,the entire DPRCS (400) area, possibly including the hamper staging area,may be enclosed within a biological containment system or isolatedenvironment to segregate the process from the other processes within themail facility. This may be through a purposefully designed “clean room”type structure built into the postal facility, or may use a later addedstructure (such as, but not limited to, an inflatable structure) whichis added after construction. In a still further embodiment, the modifiedDPRCS (400) may be mounted in a mobile structure such as a modifiedenclosed over-the-road truck trailer or a shipping container.

In embodiments, the RCM (701) may be provided as a replacement for theportion (700) of the DPRCS (400) allowing for these items to be removedand replaced. Alternatively, the RCM (701) could be provided as thecomponents of a kit for use to convert an existing DPRCS (400) into theDPRCS (400) with an RCM (701). In a still further embodiment, the DPRCScould be originally manufactured with an RCM (701).

FIGS. 14 through 19 provide drawings of an embodiment of an RCM, airhandling system, and DPRCS in accordance with the present invention.This embodiment is shown from multiple angles and multiple views showingstructures similar to those described and shown in FIGS. 4-13.

While the invention has been disclosed in connection with certainpreferred embodiments, this should not be taken as a limitation to allof the provided details. Modifications and variations of the describedembodiments may be made without departing from the spirit and scope ofthe invention, and other embodiments should be understood to beencompassed in the present disclosure as would be understood by those ofordinary skill in the art.

1. A residue collection system for collecting residues, the systemcomprising: a housing which substantially encloses an internal volume;at least two pinching means located within said internal volume, each ofsaid at least two pinching means compressing a mail piece passingthrough said pinching means to expel air from internal said mail piece;means for feeding said mail piece to said housing via gravity; airintake means for collecting at least a portion of said air expelled byat least one of said pinching means from said internal area and formaintaining said internal volume at a negative pressure; residuedetection means for detecting the presence of a residue if said residueis present in said portion; and air handling means for providing saidportion to said residue detection means.
 2. The residue collectionsystem of claim 1 wherein said residue is indicative of a Chemical orBiological Warfare Agent (CBWA) being present in said mail piece.
 3. Theresidue collection system of claim 1 wherein said residue collectionsystem is placed in a mail facility after of a Dual Pass Rough CullSystem (DPRCS).
 4. The residue collection system of claim 1 wherein saidmail piece is a letter.
 5. The residue collection system of claim 1wherein said mail piece is a flat.
 6. The residue collection system ofclaim 1 wherein said mail piece is part of a stream of mail wherein nomail piece is entirely covering another mail piece.
 7. The residuecollection system of claim 1, wherein said system receives a mail streamwhich has previously passed through a means for segregation.
 8. Theresidue collection system of claim 1 also including means foraerosolizing a residue present on the exterior of said mail piece, ifsaid exterior of said mail piece includes said residue.
 9. A residuecollection system for collecting residues, the system comprising: anaerosol chamber including: a housing which substantially encloses aninternal volume; a means for maintaining said internal volume at anegative pressure; a first means for compressing located within saidinternal volume and capable of compressing a mail piece passing throughsaid first means for compressing so as to expel air from internal saidmail piece; a second means for compressing located within said internalvolume and capable of compressing said mail piece passing through saidsecond means for compressing so as to expel air from internal said mailpiece; and means for providing said mail piece to said housing viagravity; means for transporting at least a portion of said air expelledfrom internal said mail piece from said internal area to a residuedetector.
 10. The residue collection system of claim 1 wherein said airexpelled from internal said mail piece includes a residue indicative ofa Chemical or Biological Warfare Agent (CBWA) present in said mailpiece.
 11. The residue collection system of claim 1 wherein said residuecollection system is placed in a mail facility after of a Dual PassRough Cull System (DPRCS).
 12. The residue collection system of claim 1wherein said mail piece is a letter.
 13. The residue collection systemof claim 1 wherein said mail piece is a flat.
 14. The residue collectionsystem of claim 1 wherein said mail piece is part of a stream of mailwherein no mail piece is entirely covering another mail piece.
 15. Theresidue collection system of claim 1, wherein said system receives amail stream which has previously passed through a means for segregation.16. The residue collection system of claim 1 also including means foraerosolizing a residue present on the exterior of said mail piece, ifsaid exterior of said mail piece includes said residue.